The vehicular headlamp includes a so-called projector-type vehicular headlamp in which a light source and a projection lens are arranged inside a lamp outer casing configured by a cover and a lamp housing (see, e.g., Japanese Patent Laid-Open Publication No. 2010-108727).
In such a vehicular headlamp, the light emitted from the light source is controlled to become substantially parallel by the projection lens, and the light emitted from the projection lens and formed in a predetermined light distribution pattern is irradiated toward the outside.